CA2002219A1 - Dryer sheet fabric conditioner containing fluorescent whitening agent and method for its preparation - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE
Compositions and processes for coating a flexible subs-trate for subsequent use in a mechanical tumble clothes dryer are disclosed. The compositions incorporating fluorescent whitening agents impart improved whiteness to clothes treated in the dryer and the process provides a substantially safe and easy method for incorporating the fluorescent whitening agent into the coating composition.

Description

22~9 C 6068 Ca _MPROVED DRYER SHEET FABRIC CONDITIONER CONTAINING FLUORESCENT
WHITENING AGENT AND A METHOD FOR ITS PREPARATION

BACKGROUND OF THE INVENTION

The instant invention relates generally to application of adjuvants to fabrics in tumbler-type automatic dryers. More part_cularly to articles, methods of preparation and n,ethods of use for applying these adjuvants.

It has been customary for many years to include various adjuvants in detergents and rinse or wash-cycle additives.
;~ 10 Fabric softeners and fluorescent whitening agents (FWA) which also have been called optical brighteners or fluorescent dyes are i among the most common adjuvants used.

~`~ In the wash or rinse cycles, the primary objective is to remove soil, etc. from the cloth being washed by means of detergents, water and emulsifying agents. The presence of deter-gents and emulsifying agents effective to remove soil from the cloth manifestly renders difficult and less efficient the concur-rent application of fabric softeners or other adjuvants to the same piece of material. Since the conditions characteristic of ~0 the rinsing and washing cycles, leading to inefficient applica-tion of the fabric adjuvants are not present in the drying cycle, there is the potentlal for the much more efficient utilization and application of such adjuvants.

~z~9 C 6068 Ca U.S. Patent 4,238,531 and several other .issued patents /-based on and related to this patent disclose application of FWA
and softeners, as well as many other adjuvants to fabrics in the - dryer by use of a flexible substrate carrying the adjuvant. Some commercial dryer softener sheets also employ low amounts of FWA's, for example, 7-diethylamino-4-methylcoumarin (Aclarat 8678, a trademark for a product ox Sandoz Chemical) at a level of about 0.1%.

Due to the heat, mechanical action, and residual water on the fabrics in the dryer, it might be expected that fabric adjuvants could be easily and uniformly applied in the dryer.
Experience demonstrates, however, that this does not readily occur and in the case of FWA's, it is particularly difficult.
Many patents over the last twenty or so years have dealt with ;~ 15 varlous aspects of treating fabrics in the dryer or in both the washer and dryer, and these will be well known to the artisan.
;~ Fairly extensive listings of patents dealing with compositions, substrates and with methods of treating fabrics may be found in : U.S. Patents 3,442,692; 3,895,128; 4,022,938; 4,085,052;
4,113,630, 4,177,151 and 4,199,465. Patents dealing with FWA's or optical brighteners and optical brighteners with fabrics are numerous. Several~of these are U.S. 2,784,183 on monotriazoles and U.S. 2,612,501 concerned with triazines; U.S. 3,904,533 and 4,460,485 on liquid fabric conditioning agents incorporating .

z~9 C 6068 Ca brighteners and European Patent Application 0 006 271 dealing with washing and softening compositions containing a nonionic brightener. None of the art, however, has provided completely satisfactory whitening.

In its widest aspect, the invention provides a fabric conditioning composition containing an effective amount of a distyrylbiphenyl type of FWA in combination with a selected fab-ric softener or mixture of fabric softener and distributing agent. In some instances, selected carboxylic acids which have softening properties may be employed. The inventive process pro-vides a mixed solvent system balancing water and compatible hydroxylic solvents, such as glycols or glycerine, particularly glycerine, capable of substantially dissolving the optical brightener and solubilizing it to mix with the other components of the composition to facilitate coating of the substrate and distribution of the actives.

; The fabric conditioning composition according to the present invention includes compounds generally classified as fab-ric softeners that are employed during the drying cycle of the home iaundering operation. Such fabric softeners are inorganic clays or water-soiuble or water-dispersible organic, waxy materi-als having a preferred melting (or softening) point between about 25C and 150C. Softener materials of this type may also be fab-~2~1g ric substantive in the sense that they are readily deposited onto the surfaces of fabrics treated therewith Many fabric softeners of this type also impart some degree of static control Jo k fabrics being treated therewith.

The fabric softeners can be used singly or, in admixture with one or more compatible fabric softeners. They can be selected from the following broadly denoted classes of compounds which contain at least one long chain group:

(1) cationic quaternary ammonium salts including quaternary imidazolinium salts;

(2) nonionic compounds, such as sorbitan esters, terti-ary amine oxides and ethyoxylated alcohols and I; alkylphenols;

(3) anionic soaps, sulfates and sulfonates, e.g. fatty acid soaps, ethoxylated alcohol sulfates and sodium alkyl sulfates, alkyl sulfonates, sodium alkylbenzene sulfonates, and sodium or potassium alkylglycerylethersulfonates;
:

(4) zwitterlonic quaternary ammonium `compounds;

2;~g C 6068 Ca (5) ampholytic tertiary ammonium compounds;

(6) smectite type inorganic clays and (7~ selected fatty acids.

These softeners are more definitively described in U.S. Patent 4,134,838 incorporated herein by reference. Distributing agents ,-such as those disclosed in U.S. 4,238,531 and 4,327,133 herein : incorporated by reference may also be used, for example, polyeth-ylene glycol monostearate or long chain carboxylic acids such as commercial stearic acid and the like. The amount of distributing l.0 agent should be at least 5% of the composition and should be suf-ficient to substantially distribute the composition in use.

)2Z~9 C 6068 Ca Fluorescent Whitening Agent In addition to the fabric conditioning materials and distributing agents, a fluorescent whitening agent is required.
The FWA of the invention is the distyrylbiphenyl compound of Formula I. Formula I is an ionic formula but it will be realized that the FWA is available as the sodium salt. Formula I is as follows:

FORI~:ULA I

CH=CH CH=CH ~3 ; 503 2~022~9 C 6068 Ca The optical brightener must be present in an amount of at least 1% by weight of the formulation as coated on the substrate and not more than about 5%, preferably at least 1.3%. This type of brightener, together with a softener on a foam dryer substrate, is disclosed in Example 1 of U.S. Patent 4,526,694. The brightener is also disclosed in an article by 0. I. Neiditch in the Journal of the A:nerican Oil Chemists Society, Vol. 58, No. 2, February 1981, pages 162 to 165A and in British Patent 2,028,365.

Preparation and Use of Impregnated Substrate Fabric Conditioning Articles The fabric conditioning compositions are provided as an article of manufacture in combination with a dispensing means which effectively releases the softening compositions in a tumble dryer. Such dispensing means can be designed for single usage or for multiple uses.

One such article comprises a sponge material releasably enclosing enough of the conditioning composition to effectively impart fabric softness and brightness during several drying cycles. This multi-use article can be made by filling a hollow sponge with the composition. In use, the composition melts and I; leaches out through the pores of the sponge to soften and brighten fabrics. Such a filled sponge can be used to treat sev-f~OZ2~L~

C 6068 Ca eral loads of fabrics .in conventional dryers, and has the advan-tage that it can remain in the dryer after use and is not likely to be misplaced or lost.

Another article comprises a cloth or paper bag releasably enclosing the composition and sealed with a hardened plug of the mixture. The action and heat of the dryer opens the bag and releases the composition to perform its softening and delivery of deodorant perfume function.

A highly preferred article comprises the compositions containing the softener and whitener releasably affixed to a sheet of paper or woven or nonwoven cloth substrate. When such an article is placed in an automatic laundry dryer, the heat, moisture, distribution forces and tumbling action of the dryer removes the composition from the substrate and deposits it on the fabrics.

The sheet conformation has several advantages. For example, effective amounts of the compositions for use in conven-tional dryers can be easily sorbed onto and into the sheet substrate by a simple dipping or padding process. Thus, the user need not measure the amount of the composition necessary to obtain fabric brightness. Additionaily, the flat configuration of the sheet provides a large surface area which results in effi-cient release of the materials onto fabrics by the tumbling action of the dryer.

2CP~22~9 C 6068 Ca The water-insoluble paper, or woven or non-wo~en substrates used in the articles can have a dense, or more preferably, open or porous structure. Examples of suitably at rials which can be used as substrates herein include paper, woven cloth, and non-woven cloth. The term "cloth" herein means a woven or non-woven substrate for the articles of manufacture, as distinguished from the term "fabric" which encompasses the clothing fabrics being dried in an automatic dryer.

; It is known that most substances are able to absorb a liquid substance to some degree; however, the term "absorbent", as used herein, is intended to mean a non-woven textile substrate with an absorbent capacity (i.e., a parameter representing a substrate's ability to take up and retain a liquid) from 4 to 12, preferably 5 to 7, times its weight of water.

If the substrate is a foamed plastics material, the absorbent capacity is preferably in the range of 15 to 22, but some special foams, for example reticulated foams, can have an absorbent capacity in the range from 4 to 12.

Determination of absorbent capacity values is made by using the capacity testing procedures described in U.S. Federal Specifications (UU-T-595b), modified as follows:

1. tap water is used instead of distilled water;

_g_ ~0~2~
C 6068 Ca 2. the specimen is immersed for 30 seconds instead of 3 minutes;

3. draining time is 15 seconds instead of 1 minute; and 4. the specimen is immediately weighed on a torsion balance having a pan with turned-up edges.
Absorbent capacity values are than calculated in ; accordance with the formula given in said Specification. Based on this test, one-ply, dense bleached paper (e.g., Kraft or bond having a basls weight of about 32 pounds per 3,000 square feet) has ; an absorbent capacity of 3.5 to 4; commercially available house-hold one-ply toweling paper has a value of 5 to 6; and commercially available two-ply household toweling paper has a value of 7 to about l 9.5.

Suitable materials which can be used as a substrate in the invention~herein include, among others, sponges, paper, and woven and non-woven cloth, all having the necessary absorbency requirements defined above.

The preferred non-woven cloth substrates can generally be defined as adhesively bonded fibrous or filamentous products C 6068 Ca having a web or carded fiber structure (where the iber strength is suitable to allow carding), or comprising fibrous mats in which the fibers or filaments are distributed haphazardly or in random array (i.e. an array of fibers in a carded web wherein partial orientation of the fibers is frequently present, as well as a completely haphazard distributional orientation), or sub-stantially aligned. The fibers or filaments can be natural (e.g.
wool, silk, jute, hemp, cotton, linen, sisal, o:^ ramie) or syn-thetic (e.g. rayon, cellulose ester, polyvinyl derivatives, polyolefins, polyamides, or polyesters).

The preferred absorbent properties are particularly easy to obtain with non-woven cloths and are provided merely by build-ing up the thickness of the cloth, i e., by superimposing a plu-rality of carded webs or mats to a thickness adequate to obtain the necessary absorbent properties, or by allowing a sufficient thickness of the fibers to deposit on the screen. Any diameter or denier of the fiber (generally up to about 10 denier) can be used, inasmuch as it is the free space between each fiber that makes the thickness of t-he cloth directly related to the absorb-ent capacity of the cloth, and which, further, makes the non-woven cloth especially suitable for impregnation with a composition by means of intersectional or capillary action.

Thus, any thickness necessary to obtain the required absorbent capacity can be used.

2~ 2~9 C 6068 Ca When the substrate for the composition is a non-woven cloth made from fibers deposited haphazardly or in random array on the screen, the articles exhibit excellent strength in all directions and are not prone to tear or separate when used in the automatic clothes dryer.

Preferably, the non-woven cloth is water-laid or air-laid and is made from cellulosic fibers, particularly from regen-erated cellulose or rayon. Such non-woven cloth can be lubricated with any standard textile lubricant. Preferably, the fibers are from 5mm to 50mm in length and are from 1.5 to 5 denier. Preferably, the fibers are at least partially oriented haphazardly, and are adhesively bonded together with a hydropho-bic or substantially hydrophobic binder-resin, particularly with a nonLonic self-crosslinking acrylic polymer or polymers.
Preferably, the cloth comprises about 70% fiber and 30% binder-resin polymer by weight and has a basis weight of from about 18 to 45g per square meter.

In applying the composition to the absorbent substrate, the amount impregnated into and/or coated onto the absorbent sub-strate is conveniently in the weight ratio range of from about .
10:1 to 0.5:1 based on the ratio of total softening compositionto dry, untreated substrate (fiber plus binder). Preferably, the amount of the softening composition ranges from about 5:1 to ::

C 6068 Ca about l:l, most preferably from about 3:1 to 1:1, by weight of the dry, untreated substrate.

Following application of the liquified composition, the articles are held at room temperature until the composition substantially solidifies. The resulting dry articles, prepared at the composition substrate ratios set forth above, remain flexible; the sheet articles are suitable for packaging in rolls.
The sheet articles can optionally be slitted or punched to pro-vide a non-blocking aspect at any convenient time if desired dur-ing the manufacturing process.

' ::

2~102Z~9 C 6068 Ca The composition of the invention is preferably as follows.

Softener Base About 70% dimethyl, ditallow ammonium methyl sulfate.

About 30% Polyethylene glycol 200 monostearate (having a molec-:lar weight of about 460).

Fluorescent whitening agent :
The sodium salt of the distyryl biphenyl compound of FORMULA I.
I:
Fatty carboxylic acids may be substituted for the poly-ethylene glycol monostearate. Examples of these carboxylic acids are commercial grades of stearic acid and the like which may con-tain small amounts of other acids.

The solvent system of preference is glycerine/water and preferably the optlcal brightener is disso,lved in the glycerine/water to form a premix prior to addition to the sof-tener base. The premix may also be propylene glycol or include propylene glycol but this is not preferred. The ratio of glycerine to water is about 4:1 but may vary between about two parts glycerine to 1 part water to six parts glycerine to 1 part ZOOZZ~9 C 6068 Ca water. The total amount of the solvent system is not critical and usually is about four -to five percent of the composition, but it may be less or more depending on solubility and final coatlng requirements.

After addition of the premix to the softener base, the mixture is coated on a substrate in known manner.

The composition of the invention is preferably prepared as follows:

; The glycerin/water mixture is heated to about 180F to 200F and then the FWA is added slowly while stirring. In the case of the FWA of Formula I, the color of the premix solution is a bright yellow/green. The premix is added slowly to the sof-tener base (which is preheated to 170-180F). Once the premix is added and dissolved, perfume is added and mixed for several minutes.

Once the coating composition is prepared, the substrate is then coated by dipping or padding in known manner.

~ZZ~9 C 6068 Ca The following Examples will more fully illustrate the embodiments of this invention. All parts, percentages and pro-portions referred to herein and in the appended claims are by weight unless otherwise indicated.

Example I

This example is an initial comparison of various fluo-rescent whitening agents added both with and without solubilization. The agent of the invention is shown above in Formula I.

Experimental The fluorescent whitening agents (FWA) evaluated are listed in Table 1 along with their chemical type.

:
Table 1 Types of Fluorescent Whitening Agents "F" Dye Chemical Type I Distyrylbiphenyl II 7 Diethylamino 4-methyl coumarin III Oxazole IV Morpholino disulfonated stilbene triazole V Phenyl stilbene triazole VI Methyl ethanolamine stilbene triazine disulfonate VII Diethanolamlne disulfonated stilbene triazine 2~Z2~9 c 6068 ca 7- diethylamino - 4 -methyl coumarin ;~:

22~9 C 6068 Ca FORl'lULA I I I

1,2-BI S (5-METHYLBENZoXAYoL -2-YL) ETHYLENE

--] 8--2;~9 c 6068 ca FORMULA I V

NH NH
N NH CH=CH ~3 I`IH
SO 3 SO N--\
I?

: -19-.

22~19 c 6068 ca FORMULA V

N I) CH = Of N

I;
, : : -20-:

:

2~ZZ~
c 6068 ca FORMULA V I
^
NH NH

No CH=CH I'IH

N--CH3 SO 3 SO 3 N~--CH3 C~12C1120H CH2C~ O~C

; ' Z2~L9 C 6068 Ca FORMULA VII

' NH NH

N \~ HN CH = CH NH I/ N
>=N _ --No CH2CH2OH SO3 SO3 N--CH2C11 CH 2 C H 2 OH CH ;I CH2 OHI

I:

, : -22-:

~12~L9 C 6068 Ca Each fluorescent whitening agent was dissolved in the softener base at a level of 1.3% for the initial evaluation.
Several FWAs were difficult to dissolve, especially the agents of Formulas I, IV and VI. The FWA of Formula II was easy to dis-solve even at the relatively high level of 1.3%.

The sheets were coated as follows:

A pre-weighed amount of a combination of 70% dimethyl ditallow ammonium methyl sulfate and 30% polyethylene glycol 200 monostearate was heated to about 160F and slowly mixed. The FWA
and the perfume were then added and stirred for varying amounts of time up to two hours for Formula I. The mixture was then transferred to a coater pan and the substrate sheets coated and dried. The coated sheets were then evaluated in the dryer.
Several fabric types were used for the evaluation - cotton, cot-ton terry, nylon, Dacron and Orlon. These fabrics were prewashedwith an FWA free detergent and a 3 pound ballast load and then dried in combination with the dryer sheets on the cotton/sturdy cycle for 30 minutes. Three pieces of each fabric were removed .
after the first dryer cycle. The remainder were re-washed and again treated with the dryer sheet a total of 4 times.

After the fabrics were washed, they were evaluated both visually and instrumentally for whitening potential.
Instrumental "F" values were compiled for each fabric after 1 and Z;~L9 C 6068 Ca 4 washes. The higher the "F" value, the greater the whitening potential. The results of initial screening of the FWA's are listed in Table 2.

~;iiZ2~9 C 6068 Ca o o us t-- o d' d' o x In ED ED

Q X

o a K
a Z Ian o r :~
O o I: X
a) o a Q . I: I
X . . . . .
~0 O
I: o ~o~ o o l 3 I .~ dt Ln _ V X

I : S-l H1--1 ::> H l O l >
I:
~Q s e ' I: I Z t`

:

~22~9 C 6068 Ca Based on the above preliminary screening, 1.3% of Formula I appeared to be the best choice; the sheets jade with Formula IV and Formula VI were not white when coated and the presence of the FWA produced a yellow sheet. Fqrmulas VII and V
gave slightly lower results on 100% cotton. Formula III was poor on cotton; its only advantage was a slight effect ox Dacron after four (4) washes. Formula II was inf-rior to Formula I on all fabrics.

The next evaluation was to determine if the use of 1.3%
of Formula I in a dryer sheet could be seen under realistic con-ditions of consumer usage. The same kind of fabrics were washed in the same manner as above but with a different commercial detergent and bleach and subsequently treated with either no sheet or a dryer sheet with 1.3% of Formula I. The instrumental results, which were also visually apparent, are listed in Table 3 below , ~02`2~L9 C 6068 Ca X ¦ . .

o x Jo I
d~l I
x I

X ¦, -S~~ dl z l l ' l : u, : 3 X
I) xl o o I:
:

I:: O
. o C ) l ;

C 6068 Ca Lower levels of the dye of Formula I were also evaluated. It was found that there was a small difference in "F"
values between 1.3% Formula I and 0.75% Formula X. When both levels were evaluated vs. a commercial detergent wash with bleach, it was found that a level of 1.3% Formula I was needed to give a visual difference. These results are reported in Table 4.

:;
I' I: :

:

-2~-~r\22~L9 C 6068 Ca ED
~0 OX
o xl a E~H d o O d' Ll~
So So En I us 5~ o a X¦ Ln Ln Jo : Jo d' Us Us q h I> ¦d~
:~ h l I (`1 I d' xl 0 o - 3 O I d' r-l I: _ V xl O O N

: H

. :~
h O
O

O
:~ V O

:

I:

Z21~
C 6068 Ca There was a slight difference between the control and 0.75% Formula I instrumentally, although visually the di~fer~
was hard to see. Formula I at l.3% showed an improvement ov2r the control.

It was desirable to improve the solubility of Formula I
in the softener base. It was found that the compound of Formula I could be rendered more soluble by preparing a premix in propyl-ene glycol and then adding it to the melted active. In this way - FWA addition times in the laboratory were reduced from about 2 hrs. to less than five minutes via the inclusion of 4% propylene glycol (basis active). Table 5 gives results of the evaluation of 0.75% Formula I with and without propylene glycol. These lev-e1s =re also compared to 1.3% Formula I.

I: .

206:)22~9 c 6068 Ca I I`
a o X
I:

I o a so u, x a us a) I o f rl X
:` t` ED
o ' Z I o ED O
: 3 ; ~~
= I) O ` o :;~, + O
V

h 0 O o_ o lY

O o 02 Zl9 C 6068 Ca Although the propylene glycol solvent greatly aids solubility, it was still desirable to achieve solubility with a less volatile solvent.

:

' ;::

- ~0~2Zl9 C 6068 Ca Example II

A second series of experiments were run to attempt to improve the solubility of the fluorescent whitening agent of Formula I. Three separate formulations were prepared utilizing three separate procedures as follows:

1 2 _ 3 Softener base 95.7 91.7 90.72 [dimethyl ditallow ammonium methyl sulfate 70%
Polyethylene Glycol 200 monostearate 30%]
-- Premix Optical Brightener 1.3 1.3 1.3 of Formula I
: Glycerine -- 4.0 4.0 Deionized Water -- -- 0.98 Perfume 3.0 3.0 3.0 100.O 100.O 100.O

.

2~9 C 6068 Ca Process parameters for the coating formulations were as follows:
Formulation # 1 2 3 Softener Base Temperature, F
Heating 220 Cooling 175 -- --Time,hours 8 -- --Premix Temperature, F -- 215-250 190 Final Coating Batch175 175 180 Temperature, F
Viscosity, cps Softener base 105 110 105 Softener base with100 90 80 Formula I (no perfume) Final 85 70 55 The first test batch (Formulation 1) contained about 1800 pounds and required approximately 8 hours for heating, addi-tion of the fluorescent whitening agent and cooling down to below 180F for perfume addition. The coating formulation contained very fine particles of optical brightener and was translucent after 2 hours of mixing at 220F. After then cooling the batch to 175F, it was noted that discoloration and odor degradation of :~, the softener base had occurred.

The glycerine/FWA premix solution presented several dif-ficulties during processing of the Formulation 2 test batch.
Initially the glycerine was heated to 210F and the fluorescent dye was slowly added, however, after addition of approximately 50% of the required weight of FWA, the premix became a thick, ;`

; -34-Z ~Z Z 9 C 6068 Ca lumpy viscous mass. The temperature of the glycerine was increased from 210F to 245-250F and addition of the FW~ way resumed. Moderate-to-heavy smoking from glycerine vaporization was noted at the elevated temperatures. The final premix was a thick, lumpy, viscous slurry that will cause slurry transfer and handling problems.

The third test batch, Formulation 3, was the best of the three proposed methods for dispersion and dissolution of the flu-; orescent whitening agent. A small amount of deionized water (0.98% of the final formula) was added to the glycerine during the heating step. The mixture was heated to 190F and the FWA
; was slowly added. The final premix was a low viscosity, transparent, green fluorescent premix solution that was easily pourable into the softener base. Viscosity values of the sof-tener base, the softener base with dye, and the final coating solution containing perfume were measured for each of the 3 test batches. These vàlues were best for Formulation #3.

Each of the formulations were used to coat substrate sheets. A small guantity of these coated dryer sheets were then I; 20 evaluated as follows:
: .
A set of coated dryer sheets from each test batch were selected and tested in the same manner as in Example I. The sheets contained similar coating weights to eliminate any bias 219 C 6068 Ca from active and fluorescent dye concentrations on whitening properties.

Several different types of test cloths, as listed, were selected and six samples of each were washed with a commercial detergent powder containing a fluorescent whitening agent together with a three-pound ballast load. The wash was bleached and then dried with one of the test dryer sheets. Three of each of the test cloths were then evaluated (lx). The remaining three test cloths and ballast load were then washed, bleached and dried : 10 with a fresh test dryer sheet three more times and again evalu-ated (4x). The results were as follows:

:
-.

Z~2219 C 6068 Ca I o O X
_~ I o o x I

I
C v O Xl on o I d1 o co a) X
En O
I
X
O Q) v Z; K
,4 Q) X o Jo o O ~~ K
IQ O
Q) O
~0 I ED O
Xl _ f , so rl .,, v a o a) o o o o . .
Ed Us o h So En O O O O

~i[)2~19 This evaluation shows the improvement in brightening over commercial sheets. The two formulations with 4% glycerine ; are directionally superior to the other one without glycerino bUt the third test batch (glycerine/water premix) delivered direc-tionally better brightening than the other two batches. Visual evaluation agrees with the instrumental data.

This invention has been described with respect to cer-tain preferred embodiments and various modifications whereof will occur to persons skilled in the art in the light of the instant specification and are to be included within the spirit and pur-view of this application and the scope of the appended claims.

'I

: ,

Claims (16)

1. A dryer sheet for treating damp fabric in a hot air tumbler fabric dryer during the drying cycle which comprises a composition comprising:

a) an amount effective to soften said fabric of a fab-ric softening ingredient;

b) a distributing agent for said fabric softening ingredient; and c) at least 1% by weight of said composition of the sodium salt of a fluorescent whitening agent of the formula:
said composition being carried on a flexible substrate.

2. A dryer sheet as defined in claim 1 wherein said fabric softening ingredient is dimethyl ditallow ammonium methyl sulfate.

3. A dryer sheet as defined in claim 2 wherein said distributing agent is selected from the group consisting of poly-ethylene glycol 200 monostearate, commercial stearic acid, and mixtures thereof.

4. A dryer sheet as defined in claim 1 wherein said fluorescent whitening agent is present in an amount of about 1%
to 5% of said composition.

5. A method for improved whitening of fabric comprising:

treating said fabric during the drying cycle in a hot air tumbler dryer while said fabric is damp by co-tumbling said damp fabric with a dryer sheet containing a composition com-prising a) an amount effective to soften said fabric of a fabric softening ingredient;

b) a distributing agent for said fabric softening ingredient; and c) at least 1% by weight of said composition of the sodium salt of a fluorescent whitening agent of the formula:

said composition being carried on a flexible substrate.

6. A method as defined in claim 5 wherein said fabric softening ingredient is dimethyl ditallow ammonium methyl sulfate.

7. A method as defined in claim 6 wherein said distrib-uting agent is selected from the group consisting of polyethylene glycol 200 monostearate, commercial stearic acid, and mixtures thereof.

8. A method as defined in claim 5 wherein said fluores-cent whitening agent is present in an amount of about 1% to 5% of said composition.

9. A dryer sheet for treating damp fabric in a hot air tumbler fabric dryer during the drying cycle which comprises a composition comprising:

a) an amount effective to soften said fabric of a fab-ric softening ingredient.

b) a distributing agent for said fabric softening ingredient; and c) at least 1% by weight of said composition of the sodium salt of a fluorescent whitening agent of the formula said composition being carried on a flexible substrate, said composition having been applied to said substrate from a coating mixture prepared by adding a premix of said fluorescent whitening agent dissolved in a glycerine/water solvent mixture to a mixture of said softening ingredient and said distributing agent.

10. A dryer sheet as defined in claim 9 wherein said fabric softening ingredient is dimethyl ditallow ammonium methyl sulfate.

11. A dryer sheet as defined in claim 10 wherein said distributing agent is selected from the group consisting of poly-ethylene glycol 200 monostearate, commercial stearic acid, and mixtures thereof.

12. A dryer sheet as defined in claim 9 wherein said fluorescent whitening agent is present in an amount of about 1%
to 5% of said composition.

13. A dryer sheet as defined in claim 11 wherein said glycerine is present in a ratio of four parts glycerine to one part water.

14. A dryer sheet as defined in claim 13 wherein said glycerine/water solvent mixture is present in an amount of about 5% of said composition.

15. A method for preparing a dryer sheet containing a composition comprising:

a) an amount effective to soften fabric of a fabric softening ingredient;

b) a distributing agent for said fabric softening ingredient; and c) at least 1% by weight of said composition of the sodium salt of a fluorescent whitening agent of the formula:

comprising:

heating said fabric softening ingredient; heating and adding said distributing agent to said fabric softening ingredient to form a softener base; mixing glycerine and water in a ratio of about two parts glycerine to one part water to six parts glycerine to one part water; adding during mixing said fluo-rescent whitening agent to a sufficient amount of said glycerine water mixture to solubilize said agent and form a pre-mix; adding said premix to said softener base to form a final coating solution;
coating a substrate with said final coating solution and conditioning said coated substrate to form a dryer sheet.

16. The composition as claimed in claim 1 and substantially as described herein.